Join us in Chat. Click link in menu bar to join. Unofficial chat day is every Friday night (US time).
0 Members and 1 Guest are viewing this topic.
Have you considered simulation?Microcontrollers will never have the processing power you are probably used to with PC's. You will have to make a lot of sacrifices . . . perhaps you can consider a palm pilot instead? I do AI stuff as well, but I like microcontrollers cause they are way smaller . . . A roach doesnt need human level reasoning abilities . . .
To control two small dc motors all you need is a motor driver IC. Just follow the datasheet for wiring instructions. You could instead use $9/each servos, which are even easier to interface with, and also have a built in control system.http://www.societyofrobots.com/actuators_servos.shtml
To interface between a PC and robot components you would need a microcontroller with a rs232 serial connection. The microcontroller handles things like reading sensors and controlling hardware while your PC does all the upper level stuff.
Maybe you should consider doing it the same way I'll be doing mine (or using a similar approach)...
Make a circular woodeen base with two DC motors (with gears) driving two symmetrically placed wheels under the chassis, and place two free rotating caster wheels at a percpendicular axis to the motor-driven wheels. Then you can add a level for batteries and motor control, and one for your laptop. I found some 12V motors-gearbox sets for $15 which will do the job of driving such a platform around...
And I plan on directly interfacing the motors through relays using a USB-parallel port converter (which can drive at least 8 relays). My design for the actual base is very simple, it's basically a stack of wooden circles or squares, joined together with wooden "spacers". I personally prefer a circular design because that way the robot is always able to rotate around its central axis, even if it is very close to a wall.
I will rely on vision to control the guidance of my robot entirely, which eliminates the needs for servos or other accelerometers or rotation sensors in my case. If you need more than that, however, you can use more parallel/USB or serial/USB adapters for additional inputs and outputs.Cost of the basic thing:Wood and screws: 0 to $25, depending if you already have some, or can get some for freeMotors: $15 x2 in my case, $30Wheels: $10 to $20Battery: 12V SLA 7AH - $20, $30 for a more powerful one (12AH I believe)Parallel-USB adapter: $10Relays, wires, transistors, resistors, etc: $15 to $25Total: between $85 and $125Which imo isn't so bad. It has the advantage that it can be quite fast and carry alot of weight (my motors are 150 RPM, ~40W each), you can scale it easily by adding additional levels using wooden "spacers", you can make it as large as you want, you can have alot of battery power, and you can easily carry one or more laptops. Laptops also have tons of obvious benefits themselves, like the large amount of CPU power, the possibility of interfacing with several webcams, bundled Wi-Fi "for free", the convenience of a real OS and a real compiler, etc... Not to mention that you may already have a laptop, like me, which is something less to buy for the project!If the look of wood really scares you, then you can always paint it, or encase the thing in metal or plastic eventually. Wood is also pretty light, which is another bonus.
Yeah, my main intention is to use computer vision and run algorithms such as neuro SLAM for naviagtion/mapping etc. and using neuro-controller evolved through genetic algorithms as the control software, and then experimenting with artificial life.
Can you provide any more info/links on the motor driver IC? That would be very helpful.
So, even if I use a laptop/PC I would neeed a microcontroller.
The highlighted part is what I'm interested in. You'll have to excuse my ignorance, but could you spell out how such a system would work and cost. I've been searching for the last week to find details of this and found very little useful info strangely. ... Holonomic symmetrix robots are always easier!
Typically any robot would cost an unavoidable MINIMUM of $100 . . . mine usually cost $400-ish . . .And wood sucks, use HDPE!http://www.societyofrobots.com/materials_hdpe.shtmlQuoteYeah, my main intention is to use computer vision and run algorithms such as neuro SLAM for naviagtion/mapping etc. and using neuro-controller evolved through genetic algorithms as the control software, and then experimenting with artificial life.Yea, a microcontroller is out of the question for that.QuoteCan you provide any more info/links on the motor driver IC? That would be very helpful. Go to digikey.com and search for LMD FET. There are many types of motor driver IC's out there, they are extremely common. These in particular I have used, and offer higher than normal current.QuoteSo, even if I use a laptop/PC I would neeed a microcontroller.You could also make the microcontroller wirelessly controlled by a PC. So the robot gets the brains of a PC without having to lug it around.Here is a thread that might help for that:http://www.societyofrobots.com/robotforum/index.php?topic=104.0I am currently designing a wireless robot microcontroller setup, and will post all details (schematic, code, parts list, etc) when I finish it . . . another 2+ months probably . . .
Quote from: timstirling on July 31, 2006, 02:26:43 PMThe highlighted part is what I'm interested in. You'll have to excuse my ignorance, but could you spell out how such a system would work and cost. I've been searching for the last week to find details of this and found very little useful info strangely. ... Holonomic symmetrix robots are always easier! Well, the USB/parallel converter cable is because my laptop has no parallel port... So it's basically an extra parallel port for your computer that hooks to a USB port. The parallel port has 8 data pins which can all be set on and off individually. This procudes some currents (3 to 5 volts at something around 200ma I believe). This can be used to drive a triac/relay circuit. Basically, the point is that flipping one of those bits (and leaving them on or off) on can drive a relay on and off, which can switch on or off the power to a powerful motor with some fixed voltage/current.I will keep things simple and drive the motors directly off the 12V battery, through the relay. Basically, I will use four relays (one for each rotational direction of the motor, wired so that they can't both let current flow at the same time to avoid shorts). It's possible to make this circuit more sophisticated by adding voltage regulators, and perhaps using more relays to provide the motor less power (eg: use 4 more relays to do the same but with 6 volts only, allowing your robot to move or rotate at a lower speed if necessary).But you don't even have to build this kind of parallel port relay circuitry yourself if you don't want to, some people have already done the job:http://www.electronickits.com/kit/complete/elec/ck1601.htmSome more expensive USB versions with more outputs and some inputs are also available:http://www.phidgets.com/index.php?module=pncommerce&func=itemview&KID=115439026188.8.131.52&IID=57Parallel port pinout with the 8 data pins data 0 to data 7:http://www.diyha.co.uk/electronics/parallel.html
Surprises me that you can't get it for less than 80 pounds. The site I showed you says 100$ CAN for the 0/16/16... That's about 48 pounds.